Latch



July 1o, 1951 w. M. scARBoRoUGl-l LATCH 5 Sheets-Sheet l Filed Nov. 27, 1945 1IIII. IIIIIIIIIIIIIIII.

FIG. IO

INVENTOR.

wlLLlAM M. SGARBOROUGH BY ATTORNEY July 10, l951 w. M. scARBoRoUGH 2,559,736

LATCH Filed NOV. 27, 1945 3 Sheets-Sheet 2 FIG. 4

IN V EN TOR.

WILLIAM M. SCARBOROUGH BY ATTORNEY July 10, 1951 w. M. scARBoRoUGH LATCH 3 Sheets-Sheet 3 Filed NOV. 27, 1945 FIG.9

INVENTOR. WILLIAM M. SCARBOROUGH BY {4h-fl MAQ-55.5

ATTORNEY Patented July 10, 1951 LATCH William M. Scarborough, Kenmore, N. Y., assignor to Curtiss-Wright Corporation, a corporation of Delaware Application November 2?, 1945, Serial No. 631,108

4 Claims. (Gi. 292-226) This invention relates to latches and particularly to an improved cam type latch for access doors and like closures.

The latch of the present invention is adaptable to various types of closures, and is especially applicable to installations, such as access doors on aircraft and other vehicles, where it is desirable that the door and the latch operating element be made flush with the door framing structure, and to installations where it is important that small displacing motions of the latch operating element or of the closure relative to the framing structure will not result in release of the latch.

According to the present invention the latch, preferably in the form of a cam adapted to tighten in relation to the latch keeper in response to vibration or other small displacing motions of the related parts, may be released by substantial inward movement of an operating element, such movement also resulting in outward displacement of the closure relative to the framing structure. In this manner any need for special tools to open the closure is obviated the outer surface of the structure may be devoid of handles or the like projecting elements.

The preferred embodiments of the invention include means for guiding the closure into latched relationship to its frame in which the several latch elements will function positively irrespective of minor changes in relationship due to vibration, wear or normal manufacturing tolerances.

The invention also provides a latch mechanism of simple and durable construction Whose major components may be produced of sheet metal by inexpensive stamping operations.

The foregoing and other objects and advantages will be more apparent from the following description of typical embodiments of the invention shown in the accompanying drawings, wherein:

Figure 1 is a front elevational view of an access door and surrounding framing structure with a latch in accordance .with the invention associated therewith;

Figure 2 is an enlarged rear elevational view, inverted with respect to Figure 1, of the latch mechanism and adjacent parts of the door and framing structure;

Figure 3 is a sectional view taken along line 3-3 of Figure 2;

Figure 4 is a sectional view similar to Figure 3 with the parts in unlatched condition and the door in partially opened position;

' the framing structure.

Figure 5 is a detail sectional view taken along 5-5 of Figure 3;

Figure 6 is a frontv elevational View similar t Figure 1 with an access door and the framing structure therefor provided with a modified latch mechanism;

Figure 7 is an enlarged rear elevational view, inverted with respect to Figure 6, of the latch mechanism of Figure 6 and adjacent parts of the door and its framing structure;

Figure 8 is a sectional view taken along lin 8-8 of Figure 7;

Figure 9 is a sectional view similar to Figure 8 but with the parts in unlatched relation and the L' door in partially opened position; and

Figure 10 is a sectional view similar to Figures 3 and 8 but illustrating a further modication of the invention.

As shown in Figures 1 to 3 inclusive the access door is mounted in flush relation to framing structure 2| which may comprise the skin of an airplane fuselage construction, the door being pivoted to the framing structure by a piano hinge 22 and when closed seating upon a flange 23 of Secured by rivets 24 to the framing structure is a keeper platev 25Ahaving spaced lateral extensions 2E carrying at their outer extremities a keeper pin 2'1. A latch carrying bracket 29 which may comprise a 'metal stamping of substantially channel form has iianges 32 extending outwardly from the per tion thereof provided with lateral extensions 3l secured to the inner face of the door by suitable means such as rivets 28. The spaced flanges 32 of the element 2S have extending aligned openings through which extend a pair of pins 33 and -34. Pin 33 constitutes a pivot for a latch mem! ber 35 having a cam lobe 36 for engagement with an inner face portion of the keeper 2l. A substantially opposite face portion of the pin is adapted to seat, as shown in Figure 3, in recesses fifi formed in the flanges '32', of ber 29. At one edge of the recess 4|] in each flange 32 is an inwardly extending finger portion 3l which serves to guide the member 29 into operative relation to the keeper, the fingers 3l having converging tips to facilitate their entry between extensions 26, 26 of plate 25.

Supported by the pin 34 and disposed between flanges 32, 32 is a torsion spring 38 having end portions 39, 3S bearing upon the inner face of door 20 and having a medial portion il comprising an arm adapted to bear upon an outer face portion of the keeper pin. Fivoted to the pin 33 is an actuating lever 42 which may be stamped to the pin by flanges 32, 32 of member 29.

from sheet metal into the generally channel shaped formation shown, the flanges of the lever 42' having openings passing the pivot pin 33 and being held against axial displacement relative Secured by suitable means to the free end of lever 42 is a cover plate 43 which normally closes an opening 44 in the access door 26 and is provided with a flange 45 for limiting outward movement of the cover to a position in which its outer surface is substantially flush with the outer surface of the door. Also supported by the pivot pin 33 and confined against axial movement between the latch 35 and one flange of lever v'42 is an inner'torsion spring 46 and an outer torsion spring 41.` One end portion 48 of inner spring 46 engages an arm 49 of the cam 35 for urging the latter counterclockwise as the parts are viewed in Figure 3, the other end 5| of the spring bearing against the web of channel member 29. The outer torsion spring 41 has one end portion 52 thereof bearing against the lever 42 for urging the'la'tter counterclo'ckwise tothe position there shown in Figure 3, the other end 53 of spring41 bearing Yagainst vthe web Of'the'iember 291 It will be seen that upon closing of the door the'entry of `iingers"31,`31'of'the latch a'rrying member 29- in the space between thekeeper'l and the bdyof plate v in Vvclese relationship to extensions 26, 26of keeper plate 25 will guide the parts intro therelationship` shown ii'Figure 3 wherein the keeper 21 is seated'in the recesses 4Q of 'thernember 29. After the access Adoor has been closedl small relative movement of the door 23 and the framing 'structure 2| such as these caused by vibration will'no't affect the function f 'thelatch 35 whose cam'lobei' is so designed that counter-clockwise movement of the latc'r''is constantly urged by the inner torsion'sprin'g 56, acting'to cam thekeeper into firmly Vseated relation in the recessesY 45, 40;" It Vwill also'b'e Yseen that slight inward movement of the cove'r`4`3 andlever'42 vvillnot Aaifect the latching relation'- ship of the cam witl'rY the keeper 21,' sine in the normal condition shown in" Figure 3 'tli'eex tension 49 ofthe lcam is spacedsubstantially from the web of lever 42.` In order to open" the access door the cover 43 is npressed inwardly to a Vsubstantialdegree as shovvih Figure 4. Afterinitial inward'rnovement the latch is engaged by and moves with the lever 42,"swinging`clockwise asviewedin Figures 3 and 4 to the' position shownl in the latter where the rlatch is entirely vdisengaged from keeper 21. Upon release of the latch'the torsion'spring '38 functions to effect initial opening movement of the door 20, its arm 4| pressing against the outer face of the keeper 21. With the access door 25 in the partially" open position shown in Figure 4 it can be readily grasped and moved Yto fully open position, In closing the access door, the latter is pushed inwardly against the resistance of spring 38 until the recesses'40 seat the keeper 21. In moving from the position shown'in Figure 4 to the latching position of Figure 3 the left hand face of the lcam lobe 36, as the parts are viewed in Figure 4, vwill be engaged' by the keeper andro? tated clockwise against the resistanceV of Vspring 46 'until the keeper Visv substantially'seated whereuponA the `latch spring will" effectuate latliing actin... Referring now to the embodiment of the invenf tion shown'in Figures 6, '7' and 8, the 'accessdoor |20 is pivoted by' a piano type hinge |2 `2"t`o"th e framing structure |2|. Secured to the door is a latch supporting bracket |29 substantially similar in form to the bracket 29 heretofore described. Extending between iianges |32, |32 of the bracket is a pivot pin |23 for the cam latch |35 which is urged into latching engagement with a keeper i2? by a torsion spring |46.Y The latter extends around the pin |23 and is retained between'one flange |32 of the bracket and the cam latch. 'A pin |33 also supportedY by and extending between the flanges |32, |32 carries a torsion spring |33 which functions in substantially the same manner as the spring 38 in Figures l through 5 inclusive.

The" door framing structure |2| has an opening Vi'elnornially closed by a anged cover |43 that'is secured'to an actuating lever |42. The lever is'provided with spaced ears |44 through which extends a cotter pin serving to pivot the lever to a bracket |50. This bracket is of channel form with the spaced flanges |5| thereof having openings for receiving the'pin |45 and having lateral :extensions |52, |52 to which ythe keeper |21 is joined by welding or other suitable means. The keeper bracket |56 is secured'toV the framing structure |2| by suitable fasteners |53 extending through ears |54, |54 formed on the inner lends of theflanges |5|. As shown in the drawings a reinforcing strip |55 extending around the access opening in the structure |2| 'to reinforce the latter and to provide 'a seat for the edge of' door |`2,`is disclosed between the bracket ears |54 and the member |2|. Lever`|42 is normally urged clockwise to the position shown in Figure 3 wherein the flange of cover |43 is seated upon the edge f the opening |34 by a torsion spring |56 extending about the pin |45. The spring has end portions |51 engaging the member A|55 while a medial portion thereof Aoo.institutos an' armv |58 engaging the'l'ev'o' |42. "'Theoperaton of the latch is Substantially the sameast'hat previously described, pressure applied to the cover |43 swinging the lever |42 counterclockwise from the position shown in Figure 3 until the end uit of the lever engages lobe |36 of the latch and moves the latter clockwise about its pivot pin |23 until itis disengaged'froni thekeeper |21. Upon such'diseng'ag'ement Athe spring |38 will move the door |26 to the partially opened position shown in Figure 9 vherein'it'may bereadily grasped and' moved to fully opened position. As in the case of the latch mechanism shown in Figures 1 to 5 it will be seen that slight displacement of the parts due to vibration or accidental 'inward movement of cover |43- Will not eifect release Vof the latch mechanism' but'that thev springY |46 will exert a constant urge upon the latch to over tighten the relation betwoentho latch. its keeper '|21 and the keeper seat desisnated Hill.

' Referring now to the form of the invention shown'in Figure 10, the general arrangelifl@Iiil of parts is similar to that shown in Figures 6' and 8. In this structure, however, the door 22g is provided with a reinforcing frame 2,24 to which is secured by suitable means a cast orv forged latch carrying bracket comprising'a' keeper sea-t 240,'spaced flange portions 231 for carrying vthe latch pin 223, and a flange connecting webv 233.. The latch 235 has a cam lobe 236 which, in

counter-clockwise movement of theyy latch',Y serves:

to press keeper 221 against the seat 240, such motion being urged by torsion spring' 2`43'vvl1ichA extends around the pin 2123 between 'the latch and one flange 2,31. An actual-,ing lever 242 is pivoted by a -pin 245 to a tting 250 which is secured to the closure frame 22| and which has ras an integral part thereof the keeper 221. One end of the lever carries a flanged cover 24| for normally closing an opening 222 in the frame structure.

Clockwise movement of the lever to the position shownin full lines in Figure 10, wherein the cover closes the opening 222 and wherein end portion 243 of the lever is spaced from the latch 235, is urged by a torsion spring 256 which has end portions 251 and 258 respectively engaging the fittings 250 and lever end 243. To release the latch the cover is moved inwardly, and upon travel of the lever 242 to a position wherein end 243 engages the cam, further movement will result in the latter swinging clockwise against the resistance of spring 246 to the position shown in broken lines in which it will be noted that a protuberance 241 of the latch contacts the web 238 of the latch bracket preventing further clockwise motion of the cam. Continued inward movement of the cover 24|, reflected in substantially outward movement of lever end 243 will move the latch and the closure 220 as a unit outwardly to a position wherein the closure may be grasped and moved to fully opened position. In again closing the door 220 the latch 235 will ride over the keeper 221 to the latch position shown in full lines in the drawings, it being noted that the protuberance 241 will, by contacting the seat portion 240 of the latch carrying member, limit counter-clockwise movement of the latch when the door is open to make such overriding action possible.

It will be understood that the terms inwardly, outwardly and the like, are used herein only in a relative sense to facilitate definition and not to limit the invention or its application to closures of various types.

It will be understood further that the several modifications herein specifically shown and described are merely illustrative of the inventive principles involved which may be embodied in other latch structures coming within the scope of the appended claims.

I claim:

1. In a latch mechanism, a member having spaced extensions and a keeper extending therebetween in spaced relation to said member, a second member provided with spaced flanges having recesses constituting a seat for said keeper and fingers to enter between said extensions, a cam latch for engaging a face of said keeper substantially opposed to the seat and a pivot pin for the latch extending between and carried by said anges, a pin assembly extending between and carried by said flanges, said p in assembly including a torsion spring having engagement with the keeper for urging the latter from said seat, spring means for urging thev cesses to seat the keeper and having lingers at one side of said recess for guiding cooperation with said supporting means, a pivot pin extending between andcarried by said flanges, a latch and a lever supported for pivotal movement by said pin, and a pair of torsion springs carried by said pin between said flanges, one spring acting between the second member and the latch for urging pivotal movement of the latter in a direction to retain the keeper seated in said recesses, the other spring acting independently of the first spring between the second member and the lever for urging pivotal movement of the latter in the same direction, and said lever being adapted to engage the latch after initial pivotal movement in the opposite direction for moving the latter from engagement with the keeper during subsequent movement.

3. In a latch mechanism a member having a keeper, a second member provided with spaced flanges having recesses to seat the keeper, a pivot pin extending between and carried by said flanges, a latch and a lever supported for pivotal movement by said pin, and a pair of torsion springs carried by said pin between said flanges, one spring acting between the second member and the latch for urging pivotal movement of the latter in a direction to retain the keeper seated in said recesses, the other spring acting independently of the rst spring between the second member and the lever for urging pivotal movement of the latter in the same direction, and said lever being adapted to engage the latch after initial pivotal movement in the opposite direction for moving the latter from engagement with the keeper during subsequent movement.

4. In a latch mechanism, a keeper, a member provided with spaced flanges having recesses for seating the keeper, a pivot pin extending between and carried by said flanges, and a latch pivoted by the pin between said flanges and engageable with the keeper, a torsion spring carried by the pin between said flanges for acting between the member and the latch for urging pivotal movement of the latter in one direction to retain the keeper seated in said recesses, a pin element supported by said flanges and a torsion spring element on the pin element between said flanges, said spring element being engageable with the keeper for urging it from said recesses, and said latch having a part engageable with one of said elements to limit pivotal movement of the latch in the opposite direction.

WILLIAM M. SCARBOROUGH.

REFERENCE S CITED The following references are of record in the flle of this patent:

UNITED STATES PATENTS Number Name Date 848,731 Edwards Apr. 2, 1907 1,192,221 Whitford et al June 30, 1914 1,563,489 Hooppaw et al. Dec. 1, 1925 1,607,263 Ledwinka Nov. 16, 1926 1,929,775 De Voe Oct. 10, 1933 2,012,732 Schmidgall Aug. 27, 1935 2,016,895 Ford Oct, 8, 1935 2,196,049 Andres Apr. 2, 1940 FOREIGN PATENTS Number Country Date 615,407 France Jan. 7, 1926 673,453 Germany Mar. 22, 1939 

